文件调用函数open

1、以读方式打开一个文件对象，当文件不存在时，会抛出一个FileNotFoundError

f = open('a.txt','r')
f.read()
f.close()

Traceback (most recent call last):
  File "F:/vicpy/std/day1/login.py", line 3, in <module>
    f = open('b.txt','r')
FileNotFoundError: [Errno 2] No such file or directory: 'b.txt'

2、以写方式打开一个文件对象，当文件不存在时，会自动创建此文件

f = open('a.txt','w')
f.write("hello")
f.close()

3、open函数简单使用

f1 = open('a.txt','w')
f1.write("hello world!\n")
f1.write("welcome!!!")
f1.close()
f2 = open('a.txt','r')
a = f2.read()
print(a)
f2.close()

hello world!
welcome!!!